Ski boot buckle



FIG. 1 is a top plan view of a ski boot buckle showing my new design;

FIG. 2 is a bottom plan view;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a left end elevational view; and

FIG. 5 is a right end elevational view. 

The ornamental design for a ski boot buckle, as shown. 